1. Field of the Invention
The present invention relates to the field of shoppers' computing devices, and in particular, to hand-held computing devices for computing and accumulating price data from data manually entered by the shopper.
2. Description of the Prior Art
Prior art literature discloses a number of devices for computing a sale price. In various stages of sophistication, the prior art discloses a mechanical price computing mechanism (Kellogg--U.S. Pat. No. 2,716,520), electromechanical (Karp--U.S. Pat. No. 3,262,639) and electronic (Cousins, Jr.--U.S. Pat. No. 3,806,711). Such inventions typically compute sale prices based on entry of price per unit and number of units. Data entry is accomplished by automatic measuring devices (e.g. Newell--U.S. Pat. No. 4,039,805), by automatic tag-reading systems (e.g. Gogulski--U.S. Pat. No. 4,071,740), and by manual key entry (e.g. Cousins, Jr.--U.S. Pat. No. 3,806,711).
Many of the prior art calculation devices are quite specialized and complex. Such specialization and complexity make many prior art devices not suitable for use by an ordinary consumer, for example, in a supermarket. Inasmuch as prior art units are expensive and often bulky, the normal shopper will choose an unsophisticated device for use in such an environment.
Marketing strategies used by supermarkets and similar establishments have further complicated the consumer's problems. Although unit pricing schemes, sometimes required by law, tend to aid consumers making buying decisions, such systems become quite complicated when combined with product price reduction ("cents off") coupons. To further complicate the situation, retailers may redeem coupons at double or even triple their face amount, and not all products are quoted in unit prices based on identical units. Accordingly, there has been a need for a sophisticated yet simple to operate system particularly suited to supermarket shoppers. The present invention is intended to fill that need.